Clomifene citrate or unstimulated intrauterine insemination compared with expectant management for unexplained infertility: pragmatic randomised controlled trial

Cumulative pregnancy probabilities among couples with subfertility: effects of varying treatments

OBJECTIVE

To model the cumulative probability of pregnancy among couples with subfertility without a definitive diagnosis, according to different treatment strategies.

DESIGN

A beta distribution of fecundity was fitted that reproduced the cumulative probability of pregnancy in prospective studies of natural fertility, and this distribution was applied to simulated cohorts starting with one million couples each. Probabilities of pregnancy were generated for each cycle of each couple.

SETTING

Simulation study.

PATIENT(S)

Hypothetic subfertile population.

INTERVENTION(S)

After 2 or 4 years of attempting pregnancy and diagnostic evaluation to exclude anovulation, tubal obstruction, and severe male factor, simulated treatments were applied to the remaining nonpregnant couples, with treatment effects based on published literature.

MAIN OUTCOME MEASURE(S)

Simulated cumulative probability of pregnancy.

RESULT(S)

Initially, the cumulative probability of pregnancy was highest for early treatment with IVF, but over time, conservative treatment or frequent intercourse approached the same cumulative probability.

CONCLUSION(S)

In couples without clear indications for IVF, the main benefit of early IVF may be to shorten time to pregnancy, a benefit that must be weighed against costs and potential adverse outcomes. Couples should be encouraged to maintain regular intercourse to maximize chances of pregnancy, even after unsuccessful treatment attempts.

[Ovulation induction by means of letrozole]

BACKGROUND

Clomiphene citrate is a first line treatment of infertile anovulatory women. Although the treatment induces ovulation in most women, only one in four achieve uncomplicated pregnancy after treatment over several cycles. During recent years several clinics have started to use letrozole tablets for ovulation induction. This paper gives a short presentation of letrozole, mechanisms of action are explained, and pros and cons of letrozole versus clomiphene citrate are discussed.

MATERIAL AND METHODS

The paper is based on more than two years of clinical experience with use of letrozole for ovulation induction before timed sexual intercourse or intrauterine insemination and the use of letrozole during ovarian stimulation for in vitro fertilization. In addition, a non-systematic search in Pubmed has been performed to give an overview of what is known about letrozole for ovulation induction.

RESULTS

Use of letrozole is associated with a higher chance of uncomplicated pregnancy and a lower risk of multiple pregnancy than clomiphene citrate. In addition, more than 60 % of the women who are resistant to clomiphene citrate ovulate after treatment with letrozole. Letrozole combined with gonadotropin may also be beneficial in some women during in vitro fertilization.

INTERPRETATION

Studies of letrozole use in reproduction have so far been promising. However, large randomized studies are warranted before it can be concluded that letrozole should become a first line treatment for ovulation induction.

Intra-uterine insemination for unexplained subfertility

BACKGROUND

Intra-uterine insemination (IUI) is a widely used fertility treatment for couples with unexplained subfertility. Although IUI is less invasive and less expensive than in vitro fertilisation (IVF), the safety of IUI in combination with ovarian hyperstimulation (OH) is debated. The main concern about IUI treatment with OH is the increase in multiple pregnancy rates.

OBJECTIVES

To determine whether for couples with unexplained subfertility IUI improves the live birth rate compared with timed intercourse (TI), both with and without ovarian hyperstimulation.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorder and Subfertility Group Trials Register (searched March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 4), MEDLINE (1966 to November 2005), EMBASE (1980 to November 2005), SCIsearch and reference lists of articles. Authors of identified studies were contacted for missing or unpublished data.

SELECTION CRITERIA

Truly randomised controlled trials (RCTs) with at least one of the following comparisons were included: --IUI versus TI, both in a natural cycle; --IUI versus TI, both in a stimulated cycle; --IUI in a natural cycle versus IUI in a stimulated cycle; --IUI with OH versus TI in natural cycle; --IUI in a natural cycle versus TI with OH. Only couples with unexplained subfertility were included.

DATA COLLECTION AND ANALYSIS

Quality assessment and data extraction were performed independently by two review authors. Outcomes were extracted and the data were pooled. Subgroup analyses and sensitivity analyses were done where possible.

MAIN RESULTS

In the six trials where IUI was compared with TI, both in stimulated cycles, there was evidence of an increased chance of pregnancy (six RCTs, 517 women: OR 1.68, 95% CI 1.13 to 2.50). A significant increase in pregnancy rate was also found for women where IUI with OH was compared with IUI in a natural cycle (three RCTs, 415 women: OR 2.33, 95% CI 1.46 to 3.71). However, the trials provided insufficient data to investigate the impact of IUI with or without OH on several important outcomes including live birth, multiple pregnancies, miscarriage and risk of ovarian hyperstimulation. There was no evidence of a difference in pregnancy rate for IUI with OH compared with TI in a natural cycle (one RCT, 51 women: OR 4.05, 95% CI 0.39 to 41.87). No RCTs were found for the other two comparisons.

AUTHORS' CONCLUSIONS

There is evidence that IUI with OH increases the live birth rate compared to IUI alone. The likelihood of pregnancy was also increased for treatment with IUI compared to TI both in stimulated cycles. There is insufficient data on multiple pregnancies and other adverse events for treatment with OH. Therefore, couples should be fully informed about the risks of IUI and OH as well as alternative treatment options.